Many buildings or structures include pneumatic tube transport systems for transporting objects, such as products, components, documents, drawings or other materials from one location in the building to another. Pneumatic tube transport systems typically comprise a number of substantially hermetically sealed tubes extending between locations in a building and a mechanism for selectively evacuating air from, or forcing air into, the tubes. In use, objects are placed in a carrier vessel, typically a substantially cylindrical housing, which is placed into the pneumatic tube transport system. The vessel is then propelled through the tube by creating a zone of relatively higher pressure on one side of the carrier vessel than on the other. This may be accomplished by creating a zone of negative pressure (e.g. a vacuum) in front of the vessel or by creating a zone of positive pressure behind the vessel.
In certain settings, objects housing fluids need to be transported using the pneumatic tube transport system. For example, in the health care setting pneumatic tube transport systems are well adapted for transporting fluids such as laboratory samples, blood samples or other body fluids, or intravenous bags between areas of the building. When using pneumatic tube transport systems in such health care applications, it is desirable that the carrier vessels be suitable for transporting fluids. More particularly, it is desirable that the carrier vessels, upon closure, seal to provide substantially leak-resistant containment of fluids, which may unwontedly spill from their primary containers into the vessel. Fluids which spill from their primary containers inside the vessel may leak from the vessel into the pneumatic tube posing a health risk and resulting in a risk that the pneumatic tubes may not properly function due to the presence of fluid in the system.
Various attempts have been made to produce leak-proof or sealing pneumatic carriers. However, such carriers have suffered from various drawbacks. For instance, many prior sealing carriers have utilized a flat gasket or O-ring that forms a seal, upon compression between mating surfaces of the opposing shells of the pneumatic carrier. However, such gaskets or O-rings typically require a significant compressive force to achieve a leak-proof seal (i.e., energize the seal).
To achieve compressive forces to effectively energize the seal, prior carriers have typically utilized multi-stage latches. Such latches typically require a user to close the carrier, hook the latch, and subsequently engage the latch to further compress the gasket or O-ring. That is, the act of closing the carrier does not, by itself, form a seal. The user must 1) close the carrier and 2) latch the carrier using, for example, three-bar latch arrangements and/or sliding cam latch arrangements that provide the mechanical force multiplication necessary to energize the seal.